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Taskeen Nadkar

 

Ph D.  Student

Title:

Cognitive Radio

Supervisor(s):  Prof. U.B.Desai and Prof. S.N.Merchant    

Abstract:

Cognitive Radio
The proliferation of high data rate wireless communication services coupled with a static spectrum allocation policy, has resulted in the inequitable usage of the radio frequency spectrum. The Cognitive Radio (CR) technology is projected to alleviate this imbalance by temporarily allowing unused portions of the licensed users’ (primary users’) spectrum by the unlicensed users (secondary users) without causing harmful interference to the former’s communication. It will satiate the growing, conflicting and competing demands of the spectrum by all sectors: government, private and service providers, and will form the premise of spectrum aware Next Generation wireless networks. My work entails the following two areas pertaining to CR:

  1. Symbiotic Cooperative Relaying Architectures:
    Contrary to the conventional Sense-and-Scavenge model of CR, in this architecture the primary user seeks to enhance its own communication by leveraging other users in its vicinity, having better channel conditions, as cooperative relays for its transmission, and in return provides suitable remuneration to them. The secondary user nodes are potential candidates as relays since they are idling on the licensed spectrum when the latter's transmission is in progress. Besides, they have cognitive capabilities, which give a large amount of flexibility of reconfiguration and resource allocation during the cooperative relaying process. The secondary users can access the incentive (time or frequency) without the need for continuous spectrum sensing. SCR is a promising paradigm in the realm of CR which will improve the transmission opportunities for its participating entities. Besides, it finds many applications: improving the performance at the cell edge in cellular networks, enabling Green Communications, being some of them.

  2. Resource Allocation for OFDM-based CR:
    Radio Resource Management is an important concern of CR, the aim of which is to evaluate the available resources (power, time slots, bandwidth, etc) and assign them to meet the QoS objectives of the secondary user, within some constraints on factors (typically interference) which limit the performance of the primary user. OFDM is a widely-deployed multi-carrier modulation technology for various wireless application segments, besides being a popular choice for CR. Sub-carrier power, constellation size, sub-carrier bandwidth size and cyclic prefix are some of the parameters of the OFDM-based CR system that can be adapted to meet the requirements of a CR network.
In both the aforementioned areas, popular tools such as optimization theory, cross-layer problem formulation, game theory and signal processing concepts, besides fundamental paradigms of digital and wireless communication are applied. MATLAB software and LINGO optimization software have been used for proof of concept demonstration.

  

 

Contact Address:  SPANN Lab,

                            Electrical Engineering Department,

                            IIT Bombay,

                            Powai, Mumbai- 400 076.

 

Contact Number:  

 

Email id: taskeenn[at]ee.iitb.ac.in

 

Homepage :

Publications :

1. Book Chapters

  1. T. Nadkar, V. M. Thumar, A. Patel, M.Z.A. Khan, U. B. Desai and S. N. Merchant, “Cognitive Radio: State-of-the-Art and Mathematical Challenges”, in Mathematics in Science and Technology, Mathematical Methods, Models and Algorithms in Science and Technology, World Scientific, pp. 182-227, 2011.

2. Journals

  1. T. Nadkar, V. M. Thumar, G.P.S. Tej, S. N. Merchant and U. B. Desai, “Distributed Power Allocation for Secondary Users in a Cognitive Radio Scenario”, IEEE Transactions on Wireless Communications, Under review after first revision.

  2. T. Nadkar, V. M. Thumar, U. B. Desai and S. N. Merchant, “Symbiotic cooperative relaying in cognitive radio networks with time and frequency incentive”, Springer Telecommunication Systems Journal, Special Issue on Mobile Computing and Networking Technologies, DOI:10.1007/s11235-011-9494-4.

  3. V. M. Thumar, T. Nadkar, G.P.S. Tej, U. B. Desai and S. N. Merchant, “Power allocation, bit loading and subcarrier bandwidth sizing for OFDM-based cognitive radio”, EURASIP Journal on Wireless Communications and Networking 2011, 2011:87.

  4. T. Nadkar, V. M. Thumar, G.P.S Tej, S. N. Merchant and U. B. Desai, “Adaptive Guard Interval and Power Allocation for OFDM based Cognitive Radio,” ICACT Journal on Communication Technology, vol. 2, issue 2, pp. 314-322, June 2011.

3. Conferences

  1. T. Nadkar, V. M. Thumar, G. Shenoy, U. B. Desai and S. N. Merchant, “Cognitive Relaying with Frequency Incentive,” in Proc. of the IEEE Global Telecommunications Conference, IEEE GLOBECOM 2011, accepted.

  2. T. Nadkar, V. M. Thumar, G. Shenoy, U. B. Desai and S. N. Merchant, “Cognitive Relaying with Time Incentive: Protocol Design for Multiple Primary Users,” in Proc. of IEEE Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC 11), 2011.

  3. V. M. Thumar, T. Nadkar, G. Shenoy, U. B. Desai and S. N. Merchant, “Cognitive Relaying with Time Incentive: Multiple Primary Users,” in Proc. of IEEE Vehicular Technology Conference (VTC 11), 2011.

  4. T. Nadkar, V. M. Thumar, U. B. Desai and S. N. Merchant, “A Crosslayer Framework for Symbiotic Relaying in Cognitive Radio Networks,” in Proc. of IEEE Symposium on New Frontiers in Dynamic Spectrum Access Networks (DySPAN), pp.498-509, 2011.

  5. V. M. Thumar, T. Nadkar, U. B. Desai and S. N. Merchant, “Utility-based Decision-making for Symbiotic Cooperative Relaying in Cognitive Radio Networks”, in Proc. of European Wireless Conference (EW’11), pp. 1-7, 2011.

  6. G. Tej, T. Nadkar, V. M. Thumar, U. B. Desai and S. N. Merchant, “Power Allocation in Cognitive Radio: Single and Multiple Secondary Users”, in Proc. of IEEE Wireless Communications and Networking Conference (WCNC'11), pp. 1420 -1425, 2011.

  7. V. M. Thumar, T. Nadkar, U. B. Desai and S. N. Merchant, “A Decoupled Cross-layer design for Symbiotic Cognitive Relaying with Time Incentive”, in Proc. of Wireless and Optical Communications Conference (WOCC’11), pp. 1-6, 2011.

  8. V. M. Thumar, G. Tej, , T. Nadkar, U. B. Desai and S. N. Merchant, “Adaptive power allocation for secondary users in Cognitive Radio Networks”, in 2nd UK-India-IDRC International Workshop on Cognitive Wireless Systems (UKIWCWS'10), pp. 1-5, 2010.

  9. T. Nadkar, V. M. Thumar, U. B. Desai and S. N. Merchant, “Optimum bit loading for cognitive relaying”, in Proc. of IEEE Wireless Communications and Networking Conference (WCNC'10), pp. 1 - 6, 2010.

  10. T. Nadkar, V. M. Thumar, U. B. Desai and S. N. Merchant, “Adaptive constellation sizing for OFDM-based cognitive radio networks”, in Proc. of IEEE Radio and Wireless symposium (RWS'09), 2009.

  11. T. Nadkar, V. Thumar, U.B.Desai, S.N. Merchant, “Judicious Power Loading for a Cognitive Relay Scenario”, in Proc. of IEEE Malaysia International Conference on Communications (MICC’ 09), 2009.

  12. T. Nadkar, V. Thumar, U.B.Desai, S.N. Merchant, “Power allocation for OFDM- based cognitive Relay Network”, in Proc. of IEEE International Symposium on Intelligent Signal Processing and Communications Systems (ISPACS’ 09), pp. 327-330, 2009.

  13. T. Nadkar and S. Unnikrishnan, “A Bluetooth-based Telemedicine Model-A Simulation approach”, in Proc. of SPIT-IEEE Colloquium and International Conference, 2008.

  14. T. Nadkar and S. Unnikrishnan, “Mutual Interference in Bluetooth-based sensor Networks”, in Proc. of National Conference on Nascent Technologies in Engineering, (NCNTE-08), 2008.

  15. T. Nadkar and S. Unnikrishnan, “Coexistence Modeling of Bluetooth and Wi-Fi”, in Proc. of Electro Infocom 07, National Conference on Trends and Challenges in Electronics, Communications, Information & Computer Technology, 2007.

  16. T. Nadkar, “Signal Processing to Unravel the Genetic Code”, in Proc. of National Conference on Applications of Digital Signal Processing, (NCDSP 07), 2007.

  17. T. Nadkar and S. Unnikrishnan, “Performance of the Bluetooth RF Layer”, in National Conference on Applications of Digital Signal Processing (NCDSP 07) , 2007.

  18. T. Nadkar and S. Unnikrishnan, “The Fight for Survival in the 2.4 GHz ISM Band”, in Proc. of National Conference on Technology for Societal Transformation, Utkarsh07, 2007.

  19. T. Nadkar and S. Unnikrishnan, “Simulation of Bluetooth Scatternet for Performance Evaluation”, in Proc. of International Conference on Wireless Networks (ICWN'07), pp. 82-85, 2007.

  20. T. Nadkar and T. Harhare, “Deployment of Wireless Technologies for Metro Access and the Advent of WiMax”, in Proc. of TeleTech05, National Conference organized by the Institute of Electronics and Telecommunication Engineers (IETE), 2005.

 

 


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